In looking at the diagram blowup of the GAIA on the IsoAcoustic website, I came to the conclusion that whatever isolation they are providing must be by way of some sort of rubber. They say it's not Sorbothane, but may it be Navcom? That stuff is still being made, and is used in firearms and other fields as mechanical dampers. I doubt it's the EAR rubber, but who knows?
I hope it's not, as the isolation properties of rubber doesn't extend very low in frequency, which is what we want. The lower the better. But remember when everyone ditched the springs in their VPI HW-19 tables for the SIMS Silencer Navcom pucks? Not all springs are created equal, and I don't think Geoff is going to share his secrets!
If I had the dough, I'd have a Herzan or Minus K under everything. Audiogoner folkfreak has his table on a Herzan (he had me over for a listen), and it's a thing of beauty!